Drive assembly for document feeder



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Feb. 15, 1966 R. A. DUNN DRIVE ASSEMBLY FOR DOCUMENT FEEDER Filed June 10, 1964 United States Patent Ofi 3,234,809 Patented Feb. 15, 1966 ice 3,234,809 DRIVE ASSEMBLY FOR DOCUMENT FEEDER Robert A. Dunn, Willowick, Ohio, assignor to Addressagraph-Multigraph Corporation, Cleveland, Ohio, a corporation of Delaware Filed June 10, 1964, Ser. No. 374,075 4 Claims. (Ci. 74-423) This invention relates to document feeding and especially to improved means for driving document moving rollers in document handling equipment such as card sorters and the like.

In equipment of the type in question it is common to provide several feed rollers in a series, spaced at short intervals along a track which guides the document in its travel. There is normally a common drive shaft extending along one side of the track, and this shaft is connected by bevel gearing to each of the rollers to drive them all in concert.

Since the equipment must usually operate at high speed for extended periods, these bevel gear transmissions, unless fitted with extreme accuracy, are focal points for wear, noise and failure. The organization is such, however, that accurate fitting of the gears presents severe assembly problems. The gears are in closed protective preferably one-piece housings which prevent the accessibility necessary to hand fitting of the gear mesh in. the normal way, and the housings are closely spaced and must be restricted in size to meet the dimension limitations of the equipment, thus compounding the assembly diificulties.

Accordingly it is a primary object of the present invention to provide roller drive means for document feeding so arranged that the gearing can be nicely adjusted for mesh in spite of closed housings and restricted quarters.

A feature of the present invention is the arrangement of the rotary shaft bearings in a manner to receive gear hubs instead of the shafts themselves in order to conserve space and still allow the use of pieces of full strength and readily manageable size.

Another feature of the invention is the provision of gear housings with shouldered bores so arranged that accurate assembly of gears can be had by using measured gears and shims of known thickness, whereby the cumbersome method of hand test assembly can be by-passed, and the gears accurately assembled for long life operation in spite of their being disposed in closed one-piece housings where they would normally be inaccessible for checking of mesh by the assembler.

A f urther feature of the invention is the provision of an improved method for assembling bevel gears whereby extreme accuracy of mesh may be achieved without relying heavily on the skill of the assembler.

Other objects, features and advantages will appear hereinafter as the description proceeds.

In the drawing:

FIG. 1 is a side elevation of a portion of the track of a card feeding device in accordance with the present invention;

FIG. 2 is a section taken substantially on line 2-2 of FIG. 1, but showing the gear housing in elevation;

FIG. 3 is a detail section of the gear housing of FIGS. 1 and 2, substantially on line 2--2 of FIG. 1, but to a larger scale; and

FIG. 4 is a partial detail section taken substantially on line 44 of FIG. 3.

Referring to the drawing the track is made up primarily of an elongate casting 11 including side members 11a and 11b, connected by integral transverse webs such as 12, which casting supports within itself a tray 13 suitably fastened to the casting 11 and along which the card or document slides as it is being fed. Beneath the tray 13 and projecting slightly through openings therein are the powered rollers 15 which are integrally associated with shafts such as 17 (FIG. 2). Each of the shafts 17 is mounted in bearings 19 supported by the side members of the casting. Both bearings 19 are preferably axially loaded by circular leaf springs 21 in order to remove play and provide quiet operation. The leaf spring 21 at side member 11a is backed up by a plate 23 suitably fastened to the face of the casting, and the leaf spring 21 at side member 11b is backed up by a snap ring 25 disposed in a suitable groove formed on the interior of a bore 27 through which a reduced, extended, drive connection end 29 of the shaft 17 projects. In the preferred form shown the drive connection at 29 takes the form of splines.

Each bore 27 is closed by a gear housing 31 suitably fastened to the outside surface of side member 11b, as by screws 27. The portion of the housing facing the side member 11b has a stepped bore having a small diameter portion 35 terminating in a shoulder 37 and a concentric larger diameter portion 39 terminating in a shoulder 41. A pilot ring 43 joins the bore portion 39 of the gear housing and the bore 27 of the side member 11b. Its outside diameter snugly fits both bores to insure proper alignment.

For driving the shaft 17, its splined end 29 carries a bevel gear 45. The latter has an elongatehub 47 which is interiorly splined to match the splines 29. It will be understood, of course, that any torque transmitting connection which permits relative axial positioning of the parts may be substituted for splines 29, and for convenience such a drive will be referred to hereinafter as an axial shift torque transmitting drive means. Situated on the outside of the hub are a pair of ball bearings 49, duplexed in a sense such that their lines of ball-to-race contact converge and intersect externally of the bearings. The inner race of the axially innermost bearing of the pair seats against a shoulder 51 on the gear 45, and a clamp nut 53 threaded on the end of hub 47 engages the inner race of the outermost bearing and maintains the axial loading required for duplexing of the bearings. It will be understood, of course, that duplexing involves grinding a very slight amount from the contact faces of the inner races of a bearing set so as to allow the inner races to rest closer together than the outer races by a few ten thousandths of an inch under an end clamping load, and that this is a previously known arrangement for so assembling ball bearings as to eliminate end play and add greater mounting rigidity against cocking loads for any given bearing spacing.

The assembly including the gear 45 and duplexed bearings 49 seats in the smaller diameter bore 35 of housing 31. It is held in place therein by a retainer plate 55 suitably fastened to the housing as by screws, one of which is shown at 57.

When high quality bevel gears are manufactured, they are made in pairs intended for use with each other. At the time of manufacture it is feasible for the manufacturer to take an exact measurement of the distance from a fixed location on the gear, e.g. the shoulder 51, to the axis of the mating gear. This measurement can be taken very accurately (e.g. to tenths of thousandths) and can be marked on the gear in question as an incident to its manufacture. It is likewise possible, with a suitably designed gauge, to take a similarly accurate measurement from the shoulder 37 of housing 31 to some reference surface indicative of the location of the axis of the bore which will support a mating gear to be hereinafter described. This figure is likewise marked on the housing somewhere adjacent to the shoulder 37.

The design is so planned that these two measurements Will never coincide and the former, or gear measurement,

will always exceed the latter, or housing measurement, by a small increment.

For practical purposes the innermost end of the outer bearing race of the duplexed bearing 49 may be considered as coplanar with shoulder 51. The assembly of gear 45 with its bearings 49 into housing 31 can now be eifected in such a Way as to place the gear 45 in the exact position to mesh properly wit-h its companion gear. Moverover, this can be accomplished without any hand trial of the mesh by the assembler as is customary where accuracy of the presently indicated order is needed.

The assembly is accomplished by providing a selection of shim rings of various thicknesses, graduated in small steps of the order of about .0001 to .0005". These will usually be made by a random process, accurately measured, marked with the measured value, and then sorted. When the assembly is to be made the measurement marked on the housing 31 and applicable to shoulder 37 is subtracted from the measurement on gear 45, and the shim rings checked to find one of suitable thickness, for example one having a marked measurement within about .0001" to .0005" of the above-noted difference. The selected ring is then placed in bore 35 and against shoulder 37 as indicated at 5%! in FIG. 3, and the gear and bearing asembly 45, 47, 49 inserted thereagainst. Plate 55 can then be fastened to place to hold the parts in assembled position. This places the gear 45 in precisely the appointed position for meshing accurately and smoothly with its companion gear when the latter is put in place by a similarly accurate prelocating procedure.

Extending lengthwise of the casting 11 is a main drive shaft 61 powered by a prime mover, not shown. This shaft passes through a small opening 63 in one end of each housing 31 and is concentric with a large bore 35a which is perpendicular to the bore 35 and opens at the right of each housing. The shaft 61 has formed thereon a plurality of short splined enlargements 2% which are so spaced as to be properly positioned, one within each of the housings 31. Meshed with each such splined portion is an internally splined gear 45a which in each case is the companion gear which was co-manufactured with the gear 4-5 with which it is associated. The mounting of the gears 45a within their bores 35a is accomplished in the same manner as was the mounting of the gears 45 within bores 35. The corresponding parts are given the same reference characters, but with the suffix a appended. Inasmuch as the nature of the parts and their method of assembly is identical, this operation may be clearly understood from the previous description and so the same is not repeated at this point.

By reason of the gears 47a being supported by bearings 49a, the shaft 61 is sufi'lciently guided and no further bearing supports are required. Due to this the length of the housings 31 measured along shaft 61 can be held to a minimum so that the housings can be placed in close proximity to each other as is frequently necessary due to the requirements in document feeding appllcations for rollers with certain predetermined relatively close spacing.

As will be readily appreciated, the documents are held in contact with the powered rollers 15 by idler rollers 71 which are carried on transverse support members 73. The members 73 are :preferably removably supported on the casting 11 by being received in notches 75 therein and having openings which receive pins 77 mounted in the notches. Releasable spring clips 79 slidably connected With supports 73 engage under suitable heads on pins 77 to retain the parts in operative position.

From the foregoing it can be seen that the present invention provides an improved drive train for document feeding rollers embodying special compactness benefits, in addition to providing an improved assembly method for installing bevel bears in a one-piece housing.

While preferred embodiments of the invention have been described and illustrated, it is to be understood that these are capable of variation and modification. Accordingly, the aim in the appended claims is to cover all such variations and modifications as may fall within the true spirit of the invention.

What is claimed is:

l. A bevel gear drive assembly comprising a housing having perpendicular bores meeting in a gear chamber; an outwardly facing shoulder in each bore; a shaft projecting into each bore; two meshed bevel gears each having an elongate hub and each embracing one of said shafts, said hubs terminating in an outwardly facing shoulder adjacent the gears; axial shift torque transmitting drive means connecting each shaft and its associated bevel gear; a bearing surrounding each hub; means on each hub clamping the corresponding bearing against the hub shoulder, each bearing having an exterior dimension such as to overlap the corresponding housing shoulder, a shim between each bearing and its corresponding housing shoulder; and means adjacent the other end of each bearing and engageable with the housing for retaining the same against the corresponding shim, and the latter in tight engagement with its housing shoulder for accurately locating each of the gears in an axial direction.

2. A device as set forth in claim 1 in which the bevel gears are companions forming a matched pair, in which each of said gears bears indicia indicative of the distance between its shoulder and the axis of the companion gear when properly meshed, in which the housing bears two sets of indicia, one for each bore, indicative of the distance between the shoulder for the corresponding bore and the axis of the perpendicular bore, and in which each shim has a thickness equal within close tolerances to the difference between the measurements marked on the related bore and gear.

3. The method of making a bevel gear assembly which comprises providing a housing with perpendicular bores intersecting in a gear chamber and each having an outwardly facing shoulder; providing a pair of companion bevel gears forming a matched set and each having a reference shoulder; accurately measuring the distance from the reference shoulder of each gear to the axis of its companion gear when properly meshed, and marking said measurement on the gear; accurately measuring the distance from the shoulder of each housing bore to the axis of the perpendicular bore, and marking the measurement on the housing adjacent the appropriate bore; inserting each gear into a bearing having a face coplanar with its reference shoulder when assembled to form a gear-bearing assembly; in the case of each bore, selecting a shim having a thickness equal, within close tolerances, to the difference between the measurement marked on a gear intended for the bore and the measurement assigned to the bore and placing the shim against the shoulder in the bore; and then placing the gear-bearing assembly embodying the gear intended for each bore in its respective bore with the coplanar surface of its bearing in contact with the shim therein.

4. A document feed assembly comprising a plurality of closely spaced b'ut non-touching parallel driven feed rollers each located on a predetermined fixed feed axis; a plurality of idler feed rollers, one coacting with each of said driven feed rollers; a roller shaft connected to each driven feed roller and extending into proximity to said drive shaft; a driven bevel gear having an elongate hub on each of said roller shafts connected thereto by axial shift torque transmitting drive means; a plurality of aligned driving bevel gears each meshing with one of said driven bevel gears in a direction to rotate all of them in the same sense, and each having an elongate hub; a fixed housing surrounding each meshing pair of bevel bears; ball bearings mounted in each of said housings and re- 5 6 ceiving both of the gear hubs to rotatably support both References Cited by the Examiner of the gears in each said housing; and a. drive shaft 1) normal to said :feed rollers passing through the housings, connected to each of said driving bevel gears by axial 19611323 6/1934 Aalmen 74-423 X shift torque transmitting drive means, and free of support 5 2,311,075 2/1943 0 Mauey 74-423 other than that ofiered by the hearings in said housings supporting said driving bevel gears. DON WAITE Primary Exammer- 

1. A BEVEL GEAR DRIVE ASSEMBLY COMPRISING A HOUSING HAVING PERPENDICULAR BORES MEETING IN A GEAR CHAMBER; AN OUTWARDLY FACING SHOULDER IN EACH BORE; A SHAFT PROJECTING INTO EACH BORE; TWO MESH BEVEL GEARS EACH HAVING AN ELONGATED HUB AND EACH EMBRACING ONE OF SAID SHAFTS, SAID HUBS TERMINATING IN AN OUTWARDLY FACING SHOULDER ADJACENT THE GEARS; AXIAL SHIFT TORQUE TRANSMITTING DRIVE MEANS CONNECTING EACH SHAFT AND ITS ASSOCIATED BEVEL GEAR; A BEARING SURROUNDING EACH HUB; MEANS ON EACH HUB CLAMPING THE CORRESPONDING BEARING AGAINST THE HUB SHOULDER, EACH BEARING HAVING AN EX- 